Australian airline Qantas has been ordered to check all oxygen bottles on its fleet of Boeing 747s after a large hole was ripped in the side of a flight from London to Melbourne by way of Hong Kong.  The aircraft was forced to make an emergency landing at Manila last Friday. Investigators believe an exploding oxygen cylinder may have been to blame.  From Sydney, Phil Mercer reports.

There was understandable relief on board the troubled Qantas flight when it made an emergency landing in the Philippines Friday, the drama recorded on a mobile phone by a passenger.

The mid-air crisis began when part of the Boeing 747's undercarriage blew off, triggering a loss in cabin pressure and ripping a hole the size of a small van in its side.

The flight had left Hong Kong after a stopover en route from London to the southern Australian city of Melbourne.

Passengers said they heard a loud bang before the aircraft rapidly lost altitude.

"There was an almighty crack and you could hear something happening and then the oxygen masks fell down and you started dropping down, ears popping that sort of stuff," said one of the passengers.

"I thought we were just going down into the sea, so I just grabbed my passport out of my bag and put it in my pocket so that if my body was found they could identify it," added another passenger.

Qantas has agreed to inspect oxygen bottles on its fleet of 747s.  Investigators believe exploding cylinders could be the cause of the damage.

Engineers' union leader Steve Purvinas is calling on the airline and Australia's Civil Aviation Safety Authority to investigate thoroughly.

"We just hope that Qantas and Casa now take the necessary steps to ensure that the rest of the Qantas fleet is safe to fly," said Purvinas.

All 346 passengers and 19 crew survived the drama unscathed.  Safety experts from Australia are now in the Philippines to inspect the plane.

They will investigate claims that oxygen masks aboard the plane were in poor condition and that some failed to deploy during the emergency.

Some passengers have complained that children were screaming after their masks failed and that the youngsters' lips had turned blue from lack of oxygen. 

Qantas, Australia's national airline, has a good safety record and senior management has promised to investigate thoroughly the reasons behind Friday's emergency.